The dubious honour of being the loudest mammal on Earth goes to the howler monkey of Central and South America, one of the biggest monkeys in the world. When howler monkeys call in chorus at dawn or dusk, they can be heard over a distance of 5 km. The monkey has a large throat and a specialized vocal sac that acts as a resonating chamber. Its call measures around 125 dB on the sound scale.
Mostly it uses its tail to help grip branches as it eats and moves around high in the trees. Each family group is generally made up of 15 to 20 howlers. The leader is usually an old male. The head and body of adult howler monkeys range from 22 to 36 inches (55.8 to 91.4 centimeters) long and their tail can add 23 to 36 inches (58.4 to 91.4 centimeters).
Picture Credit : Google